Research On The Uplift And Denudation Process Since The Late Cretaceous In Zhangguangcai Range,East Of Heilongjiang Province,China

The area of Zhangguangcai range is located in the eastern part of Heilongjiang Province.The tectonic location is on the eastern edge of the SongnenZhangguangcailing block.It is an orogenic belt formed by the collision between the Songnen block and the Jiamusi block during the Early-Middle Jurassic.The study area is called Tanlu Two branches of the northern segment of the fault: Jiamusi-Yitong fault and Dunhua-Mishan fault clamped.Since the Late Cretaceous,the Zhangguangcailing area has been continuously affected by the activities of the two fault zones and the Pacific plate.This paper analyzes the Zhangguangcai range using the methods of tectonic geomorphology and fission track thermochronology to determine the specific time,period and intensity of the uplift of the study area since the Late Cretaceous,and to identify the branches of the Tanlu fault and the Pacific plate The impact on the uplift of the study area.Based on the 30 m resolution DEM data of ASTER GDEM,this paper uses Arc GIS10.2 software to analyze the structure and geomorphology of the study area.The analysis results show that there are two stages of planation planes in Zhangguangcai range,which are distributed at elevations of 1600?1800m and 1200?1400m.According to the results of the geomorphic index extracted from the study area,it was identified that there is a strong uplift zone on the north and south sides of the Zhangguangcai range,which are located in the east of Mudanjiang(Zone ?)and the south of Shangzhi(Zone ?).The geomorphological evolution stages of all regions are in the middle age.The comparison of geomorphological indexes can confirm that the tectonic activity of Zone II is stronger than that of Zone I.In addition,the other areas of Zhangguangcai range are all in the old age stage,with well-developed water systems and relatively structurally relatively stable.Based on the thermal evolution simulation of apatite fission track taken in the Zhangguangcail range,this paper concludes that the Zhangguangcai range area has experienced two uplifts and one subsidence since the Late Cretaceous,with uplift times of 90?70Ma and 20 Ma,respectively.So far;the settlement time is 70?20Ma.Through the comparison of time nodes,it is found that there are differences in space.The specific manifestation is that the uplift time of the Zhangguangcai range during the Late Cretaceous and Tertiary periods migrated in a counterclockwise direction,at the end of the Late Cretaceous to the middle of the Miocene.The settlement time expands in a counterclockwise direction.By combining the results of tectonic geomorphology and fission track thermochronology,it is determined that the uplift difference of the Zhangguangcai range in the Late Cretaceous(90?70Ma)is due to the accelerated subduction of the Yizenaqi plate,which caused the branching of the Tanlu fault zone.The influence of right-lateral strike-slip movement;the difference in subsidence between the end of the Late Cretaceous and the middle Miocene(70?20 Ma)is the extension of the Pacific plate caused by the increase in the subduction angle and the branching of the Tanlu fault zone caused by the counterclockwise rotation of the subduction direction.The influence of left-handed strike-slip movement;the uplift since the Tertiary(20?0 Ma)is caused by the back-arc expansion caused by the increase in the movement rate of the Pacific plate.The current mountain morphology of Zhangguangcai Mountain is the result of the Cenozoic left-handed uplift after being formed into a mountain in the Quaternary,which was squeezed from the east-west direction and moved in a right-handed reverse translation,and then was transformed by the left-handed movement.